Rocket assisted torpedo



May 7, 1963 J. 'r. BARTLING ETAL 3,088,403 ROCKET ASSISTED TORPEDO Filed May 26; 1959 3 Sheets-Sheet J.

INVENTORS.

JAMES T. BARTLING ORVILLE J. SAHOLT BERNARD SMITH BY 9. 2m

ATTOR'NEYE.

y 7, 1963 J. T. BARTLING ETAL 3,088,403

ROCKET ASSISTED TORPEDO 3 She'ets-Sheet 2 Filed May 26, 1959 INVENTORS. JAMES T. BARTLING ORVILLE J. SAHOLT BERNARD SMITH :44. ATTORNEYS.

y 1963 J, T. BARTLING ETAL 3,088,403

ROCKET ASSISTED TORPEDO Filed May 26, 1959 3 Sheets-Sheet s INVENTORS. JAMES T. BARTLING ORVILLE J. SAHOLT BERNARD SMITH BY 49. @m 17/63 M ATTORNEY'S.

FIG. 8.

2 (Ilaims. (i. 1ii27) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to ordnance equipment and more particularly to improvements in a hybrid missile of the type having a high-speed ballistic airflight phase but delivering a payload anti-submarine apparatus at safely reduced water-entry speed.

It is of course the immediate purpose of anti-submarine operations to effect delivery and detonation of explosive charges within lethal distance of the enemy submarine under attack. Of present interest in such respect are the shipborne anti-submarine weapons of prior art homing torpedo type, these being launched from tubes, or catapulted into the water a short distance from the ship, such weapons in any event being characterized by an entirely or principally underwater mode of transport to the suspect target area. It might seem that such anti-submarine homing weapons would be particularly efiicacious at all times because of their target-seeking, pursuing and attack capabilities. Homing torpedoes nevertheless present limitations which are bound to seriously reduce their eifectiveness in certain tactical situations likely to be encountered in actual sea warfare. Specifically, an enemy submarine can be expected to approach a target ship closely enough to place it within range of torpedoes carried by the submarine, but not so closely as to place itself within easy reach of depth charges or homing torpedoes carried by that target ship or by escort destroyers or other warships. Prior art shipborne anti-submarine torpedoes are at an immediate disadvantage under such circumstances, since the range at which a homing torpedo can detect the presence and direction of a target submarine is no more than a small fraction of the stand-off range from which a submarine can fire its spread of torpedoes. In an attempt to overcome this difficulty, advanced types of ship-launched anti-submarine torpedoes have been designed to first proceed along a predetermined course toward the suspect area, then to enter some type of scanning search for the target, followed by switchover to a homing and pursuit phase if and when the target submarine is in fact detected. Despite such automatized sophistication of modern anti-submarine homing torpedoes, they will not have good kill probability when employed by vessels under circumstances as indicated above, due to inherent limitations of the torpedo itself as to speed, total range and target detection range, but particularly as to relatively long swim-out time which will generally enable the target submarine to have escaped from the target detection field of the ship-launched torpedoes by the time they arrive at the originally suspect area.

It has now been made possible to overcome this serious difiiculty to some extent by use of an anti-submarine weapon of the type disclosed in the copending and commonly assigned US. patent application entitled Missile, S.N. 790,976, filed February 3, 1959, by H. G. Johnson and H. Silk. Basically, such a weapon greatly reduces the delivery time by rocket-launching itself from say a destroyer or other Warship to travel at high speed above water toward a suspect target area, yet operates further to deliver its anti-submarine payload to that area at a safely reduced water-entry speed, thus avoiding malfunction problems which would otherwise be occasioned by high-speed water impact forces.

While the particular weapon as reduced to practice and as described in the said copending application has been entirely satisfactory as a prototype structure to demonstrate feasibility and operativeness of the basic invention, novel improvements in accordance with the present invention have made it possible to provide a service weapon presenting both simplification in structure and greater reliability and effectiveness in operation.

Primary objects of the present invention, therefore, are to provide improvements in an anti-submarine weapon, of the hybrid type which effects high-speed above-water delivery of an anti-submarine payload to a suspect target area, which simplify the weapon as to structure, assembly and reliability thereof.

Further objects of the invention are to provide improvements in such an anti-submarine weapon which extend the maximum range and which reduce ballistic dispersion of the weapon.

These and other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 depicts diagrammatically and in general manner the aboveawater operational characteristics of the anti-submarine weapon which the present invention concerns;

FIG. 2 illustrates the overall configuration of the improved weapon and the stationing of certain components therein;

FIG. 3 illustrates certain details of the airframe and of the torpedo and rocket motor carried thereby;

FIG. 4 is a view of the lower half of the bivalvular airframe taken along line 44 in FIG. 3;

FIG. 5 is a sectional view of the upper half of the bivalvular airframe taken along line 55 in FIG. 3;

FIG. 6 illustrates in perspective a separation fire control assembly as mounted in one of the upper rib members of the airframe;

FIG. 7 details the manner in which one of the thrust lug members secured to the airframe engages in a recess provided in the payload torpedo;

FIG. 8 is a schematic circuit diagram of the separation fire control assembly; and

FIG. 9 details the banding and cabling arrangement which severably secures the airframe to its payload torpedo.

Referring first to FIG. 1 of the drawing, there is shown diagrammatically the anti-submarine weapon 15 of the present invention and, in general manner, its airflight path and the sequence of events therealong which lead to delivery of the weapons payload 16 to the suspect water area at a safely reduced water-entry speed. Described later in greater detail, the weapon 15 comprises an airframe 17, the payload 16 extending from the forward end of the airframe and severably joined thereto, reaction propulsion means 18 which is preferably a rocket motor carried in the stern portion of airframe 17, means for separating the airframe from the payload at a predetermined instant after launching, a parachute pack secured to the stem end of the payload and arranged to deploy immediately after airframe separation, and a parachute coupling release mechanism 20 which frees the payload from the parachute at water-entry.

impelled by rocket propulsion, the weapon 15 projects itself from any suitable launcher (not shown), carried by say a destroyer or other warship 21, which may be trained at an angle of substantially 45 to provide maximum range capability. The weapon pursues an essen tially ballistic trajectory 22 at relatively high speed until, say at a point 23 which is reached at a predetermined and preselected instant associated with the particular range desired, explosive separation devices carried by the Weapon are detonated to rupture a banding arrangement and to thus release hinged members 24 of the airframe from engagement with the payload 16. The hinged members then open away from the payload, and in so doing serve as airbrakes to retard the airframe assembly relative to the payload. In the course of such retardation, a parachute-opening lanyard, extending from the packed parachute and secured to the airframe, comes under tension and breaks as the parachute canopy 27 pulls out, the airframe then breaking apart at the rear hinge structure of its hinged members 24 and tumbling free as indicated, these events taking place in a rapid sequence lasting only a fraction of a second as measured from the detonation instant. Upon deployment of parachute 27, the payload 16 continues its airfiight along a non-ballistic path toward the suspect area, the payload descending at an increasingly steep angle, as indicated, but with decrease in speed to a safe water-entry value because of parachute drag. At water entry of the payload 16, the reduction in pull force then experienced by the shroud lines 28 causes the coupling mechanism to unlock, releasing the parachute 27 and enabling the payload 16 to proceed unimpeded in its underwater phase of attack against the target submarine 29.

In view of the foregoing and as has also been indicated in the previously mentioned copending application, it will be understood that any operational system in which the anti-submarine weapon disclosed herein would be employed must of course function to detect and to determine target direction and range information, such that a separation timing circuit in the weapon itself and the training direction of the Weapon launcher may be suitably =set to result in delivery of the Weapon to the suspect or predicted target area. This presetting may be accomplished simply by operator control before launching; in its most advanced version, such a system may be fully automatized to continuously provide training orders for the weapon launcher, and timing orders for the weapon itself, so that the weapon is always suitably set and ready to be fired at any instant in the period during which the launching vessel is at suitable position and range relative to the target submarine to be attacked. Further description of the several elements of a complete system, however, is not included herein since the system may be entirely conventional and since details thereof are unnecessary to an understanding of the present invention which is concerned with improvements in the weapon per se. It should also be understood that the representation in FIG. 1 is simply schematic, and that the anti-submarine weapon 15 therein is shown in exaggerated relative size for ease of illustration.

Referring now to FIG. 2 which illustrates the configuration of the improved hybrid weapon 15 and the stationing of certain components therealong, and to FIG. 3 which illustrates in greater detail the airframe and the manner in which it severably clamps against the antisubmarine payload, the airframe 17 is essentially a bivalvular structure comprising a pair of semi-cylindrical shells 24 which are strengthened against distortion under bending moments and compressive thrust forces by means of rib members 32, these rib members in this instance extending beyond the bivalvular shells 24 as best shown in FIG. 3. Opposed arcuate bail members 33 are pivotally joined at their ends, as by short bolt means 34, and are secured to the rear extremities of rib members 32 to serve as hinging means for'the bivalvular airframe. When closed against the payload, and so maintained by a banding and cabling arrangement as later described, the hinged members 24 grasp the payload, in this instance a homing torpedo, by means of thrust lug members 35 which are secured to the rib members 32 at their forward extremities as indicated in FIG. 2 and detailed in FIGS. 4 and 6. The thrust lugs mate with scalloped recesses 36 provided in thickened shell portions of torpedo 16 as best indicated in FIGS. 2 and 7. The payload torpedo 16 is further centered and maintained in substantial alignment with the airframe by means of pad members 37, as shown in a cutaway section at the left in FIG. 3, these pad members in this instance being conveniently secured to the rib members 32 as detailed in FIG. 4.

It will be understood that the payload torpedo 16 may be conventional in all respects except for adaptive modification to engage with the airframe, for example as in the illustrated instance wherein the scalloped recesses 36 in the torpedo shell are shaped to coact with the thrust lugs of members 35, in this instance providing a wedging action to securely clamp the payload torpedo within the airframe between the thrust lugs and pad members 37, and in alignment with the thrust axis of the airframe. By way of example of typical payloads, the torpedo may if desired be of type which is self-energizing by means of depth-responsive hydrostat switch assemblies which control propulsive, electronic, steering or other circuits when the torpedo has reached a depth of say l8 feet after water-entry, or of other type wherein circuits may be energized, at some instant prior to water entry, by a timing mechanism or by any other means conventionally employed. Thus, in the event the torpedo is of type requiring that pull-wires be withdrawn from various devices therein, prior to water entry, this would of course be easily accommodated by anchoring the said pull wires directly or through lanyards to the airframe assembly 17. It may also be noted at this point that torpedo shell-mounted devices, such as the electrical connector member 38 shown in FIG. 3, or any element carried within the bivalvular airframe, may be made readily accessible as sometimes required for test, adjustment or other purposes, simply by providing a window or other cut-away in the airframe shell as indicated.

Where the torpedo happens to be of type having large elevator fins 40 which are slightly skewed, as sometimes employed with single-propeller torpedoes for underwater heel correction, airfiight stability of the weapon can be improved by use of aligned fairing vanes 41 secured to the hinged members 24 and arranged to enclose the skewed fins 40. Where the fins are not skewed, for example the rudder fins 42 in FIGS. 2 and 3, airframe 17 is simply provided with slit windows 43 through which fins 42 protrude, providing additional airfiight stability.

As indicated in FIGS. 2 and 3, rocket motor 18 is secured to the lower bivalvate member 32, by one or more straps 44 having any suitable clamping or tightening means (not shown). The rocket motor is of course supported and maintained in aligned position, as by means of pad members (not shown) similar to those provided for the payload torpedo, or by adjustable pad members where this may appear desirable, and further by means of an arcuate transverse rib 45 secured to the lower hinged member 24 and having a flange which mates with an annular groove provided near the forward end of the rocket motor, as shown. A like mating arcuate transverse rib (not shown) is secured to the upper hinged member '24, these transverse ribs thus serving to restrain the rocket motor against displacement along the airframe 17. Additional arcuate transverse ribs may be employed to improve rigidity of the semi-cylindrical shells 24 of the airframe.

In order to improve stability and to reduce ballistic dispersion of the weapon 15, the airframe is provided with a cruciform arrangement of fins 50 which may conveniently be secured to the rib members 32 as best shown in FIGS. 3 and 5. Also conveniently carried in the rib members 32 of the upper hinged member 24, for example at stations to bear against the forward portion of rocket motor 18 as indicated by FIGS. 3 and 5, are ejection springs 51 which are under compression to insure opening of the airframe when the banding arrangement is severed at the separation instant.

The present weapon includes a packed parachute which comes into play to decelerate the payload torpedo 16 after airframe separation, and a parachute coupling release mechanism 54 for jettisoning the parachute upon water impact of the torepdo. As in the previously-mentioned copending application, these may be of any suitable type normally intended for use with aircraft-launched torpedoes. While thus conventional and not further detailed, it may be noted that in the particular embodiment illustrated in FIG. 2, coupling mechanism 54 is to be understood as threadedly engaging a stub extension of the pro peller shaft upon which propeller hub 55 is mounted, and that it is secured to the canister 56 from which the parachute later deploys and to which its shroud lines are anchored. It will also be understood that for the purpose of extracting the packed parachute 27 from its canister 56 when the airframe separates from the payload torpedo as has been described, the parachute static line or lanyard 57 is anchored by any suitable means to the lower bivalve member 24.

Until released at a predetermined and prescribed instant during airflight of the weapon, the bivalvate members 24 are firmly secured in clamping engagement with both the payload torpedo 16 and rocket motor 18 by means of the separation strap and cable system shown in FIG. 3. As detailed in FIG. 9, separation strap 60, side cables 61 and overhead cable 62 terminate in fittings which engage slots in crank members 63 and 64 at both sides of the lower hinged member 24, facilitating assembly and tensioning of the strap and cable arrangement. Crank members 63 and 64 are pivotally secured to the lower hinged member 24, as by means of bolts 65 threadedly engaging crank blocks (not shown) or other thickening means secured to the said hinged member. Stop pins 66, provided as shown for the forward crank members 63 and secured to the airframe, enable the strap 60 to be separately tensioned, by tightening nuts 67 of the T-bolts 68 against the upper arms 69 of crank members 63, and to thus develop considerably greater clamping force than is required for the overhead cable 62. Overhead cable 62 may be terminated simply with ball fittings as indicated to engage against the upper arms 70 of aft crank members 64-, and one end of each of the remaining side cables 61 terminates in a threaded bolt fitting 71 to provide means for placing the cables under tension and thus securely binding the hinged members together at the forward end of rocket motor 18.

Further strengthening of the airframe against distortions which would arise from relative movement of the hinged members 24 under influence of bending moments experienced by the weapon, is provided by means of shearresisting structures at the forward portions of the hinged members. In the particular embodiment illustrated in FIG. 3, pairs of alignment blocks 72 are secured to each side of the hinged members 24, one of these blocks 72 in each pair carrying a shear-resisting pin and the other having a matching bore therein, positioned to accept the said pins during assembly of the bivalvular airframe.

Referring now to the separation fire control and straprupturing means employed to release the hinged members 24, these are provided as duplicate assemblies in each weapon 15 to reduce possibility of malfunction as to airframe separation, and again are very conveniently mounted in the upper rib members 32, at the forward ends thereof as indicated in FIG. 3. Each of the unitary assemblies 75, external appearance thereof shown in FIG. 6, in this instance carries both the separation fire control apparatus and an explosive block 76, the latter being provided as an insert unit to facilitate entry and wiring of an electrical primer type of explosive charge, and having an explosion-directing slit 77 formed therein. When the separation fire control assemblies are properly mounted in place within the upper rib members 32 as indicated in FIG. 6, the explosion-directing slits 77 are positioned to face directly against the separation strap 60 which passes across windowed regions provided in the rib members 32 as also shown in FIG. 6.

The separation fire control assemblies 75 may of course be designed to carry any desired type of separation fire control means adapted to provide an adjustable predetermined delay between the weapon launch instant and the instant at which the explosive charges are fired to separate the airframe from the payload torpedo. These assemblies 75 may consist of entirely conventional elements, such as those briefly described in connection with a typical fire control circuit as given in FIG. 8, wherein the separation fire control assembly 75 begins charging capacitor 80 very soon after the weapon is launched, and at a later instant closes switch 81 to complete the electrical circuit between capacitor 80 and primer 82 of the explosive charge. Switch 81 here forms part of and is controlled by a timing device 83 such as employed for flare fuzes, generally of clock-escapement type adapted to be pre-set to effect its switch-closing operation at any desired time-interval after release of the escapement mechanism to initiate its timing function. Such release may be accomplished by the simple yet effective conventional arrangement which employs an escapement-unlocking pull-wire 84 as indicated in FIGS. 3 and 6, in this instance operated at missile-launching by means of a lanyard 85 anchored to the launcher (not shown). As a safety measure, the capacitor charging circuit includes an arming switch 86 forming part of a conventional acceleration-responsive device 87, preferably of the type which does not close its arming switch 86 until the weapon experiences a sustained acceleration, say 10 G for a period of 1 second, which values are normally exceeded in the described embodiment. Capacitor 80 then charges to substantially the voltage delivered by source 88, charging resistor 89- being of very low ohmage compared to the protective bleeder resistor 90. The circuit element values are not critical but, by way of example, capacitor 80 may have a value of 2 microfarads, charging resistor 89 may be 0.1 megohm, bleeder resistor 90 may be 44 megohms, and source 88 may deliver 90 volts to the charging circuit.

The weapon is of course fired by applying ignition voltage, as required to detonate an igniter charge carried by the rocket motor igniter assembly 92, to an electrical connector 93 which is mounted upon the lower hinged member of the airframe structure and which connects to the igniter assembly as indicated in FIG. 3, this connector being of any conventional tape adapted to mate with a breakaway connector (not shown) having cabling which is associated with the launching apparatus and through which the ignition voltage is supplied.

As in the earliest version of this type of anti-submarine weapon as described in the previously mentioned copending application, rocket motor 18 may be of conventional IATO type ordinarily used for boosting aircraft power and acceleration at take-off, these rocket motors being available with various burning time and total impulse characteristics such that a suitable selection can be made to provide a desired maximum range for the weapon. Such range is principally dependent upon the thrust and impulse characteristics of the rocket motor, the weight of the complete weapon, and the drag of the weapon prior to separation time. In addition to other advantages, the structure improvements as disclosed make possible a significant reduction in the total weight of the weapon and correspondingly provides considerably greater maximum range capability for the weapon using any given rocket motor. As a specific example based upon the particular embodiment here described, employment of a JATO unit weighing approximately pounds and designed to deliver about l3,000' lb.-secs. total impulse over a period of 1.8 seconds, and a payload torpedo and other components, as described, which bring the total weight to approximately 560 pounds, provides a maximum safe-delivery range of approximately 4000 yards, the separation time in this instance being 23 seconds and the delivery time being about 39 seconds. Intermediate ranges are of course obtained by presetting the weapon for earlier separation times, a range of approximately 2100 yards for the described embodiment, for example, being obtained by imposing a separation time of seconds.

It will now be understood that the anti-submarine weapon as described presents significant and novel improvements in structure which reduce its weight, simplify its manufacture and assembly, extend its maximum range capability with a rocket motor of any given total impulse, and further provide a strengthened and cleaner aerodynamic configuration which increases its accuracy of delivery.

It will also be appreciated that while the detailed description of the invention has been given in terms of an embodiment specifically employing a conventional homing torpedo as the payload, other types of anti-submarine payloads may be used, e.g. of depth charge type having extremely high yield and adapted to detonate at a predetermined instant or at a predetermined depth, details of the particular payload however forming no part of the present invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In an anti-submarine weapon comprising a payload apparatus effective to operate against a submerged target submarine when delivered to a suspect water area, and an airframe of generally tubular configuration severably joined to said payload apparatus, extending rearwardly therefrom and carrying reaction propulsion means operative to project said weapon into a ballistic trajectory directed toward said suspect water area, in combination, the improved structure wherein said tubular airframe is of bivalvular configuration, said bivalvular airframe comprising a pair of semi-cylindrical shell structures hinged at their aft ends, means clamping said shell structures against said payload apparatus and in thrust association therewith, and shear-resisting means releasably mating said shell structures near the forward portions thereof, said shear-resisting means comprising a pair of alignment blocks secured to the contiguous sides of said bivalvular members respectively, one of the blocks in each pair carrying a shear-resisting pin, and the other block in said pair having a matching bore in which said pin is received.

2. In an anti-submarine weapon comprising a payload apparatus effective to operate against a submerged target submarine when delivered to a suspect water area, and an airframe of generally tubular configuration severably joined to said payload apparatus, extending rearwardly therefrom and carrying reaction propulsion means operative to project said weapon into a ballistic trajectory directed toward said suspect water area, in combination, the improved structure wherein said tubular airframe is a bivalvular configuration, said bivalvular airframe comprising a pair of semi-cylindrical shell structures hinged at their aft ends and folded forwardly toward and releasably engaging said payload apparatus, strap means releasably clamping the forward ends of said shell structures against said payload apparatus, and cabling means binding said shell structures together at a substantially central station therealong and linked to said strap means for release therewith, said cabling means being linked to said strap means by means including pivotally mounted crank members.

References Cited in the file of this patent UNITED STATES PATENTS Div. 10 and Scientific Library.

Aviation Week, vol. 68, No. 8, February 24, 1958, pp. 56, 57. Copy in Scientific Library and Div. 10. 

1. IN AN ANTI-SUBMARINE WEAPON COMPRISING A PAYLOAD APPARATUS EFFECTIVE TO OPERATE AGAINST A SUBMERGED TARGET SUBMARINE WHEN DELIVERED TO A SUSPECT WATER AREA, AND AN AIRFRAME OF GENERALLY TUBULAR CONFIGURATION SEVERABLY JOINED TO SAID PAYLOAD APPARATUS, EXTENDING REARWARDLY THEREFROM AND CARRYING REACTION PROPULSION MEANS OPERATIVE TO PROJECT SAID WEAPON INTO A BALLISTIC TRAJECTORY DIRECTED TO WARD SAID SUSPECT WATER AREA, IN COMBINATION, THE IMPROVED STRUCTURE WHEREIN SAID TUBULAR AIRFRAME IS OF BIVALVULAR CONFIGURATION, SAID BIVALVULAR AIRFRAME COMPRISING A PAIR OF SEMI-CYLINDRICAL SHELL STRUCTURES HINGED AT THEIR AFT ENDS, MEANS CLAMPING SAID SHELLSTRUCTURES AGAINST SAID PAYLOAD APPARATUS AND IN THRUST ASSOCIATION THEREWITH, AND SHEAR-RESISTING MEANS RELEASABLY MATING SAID SHELL STRUCTURES NEAR THE FORWARD PORTIONS THEREOF, SAID SHEAR-RESISTING MEANS COMPRISING A PAIR OF ALIGNMENT BLOCKS SECURED TO THE CONTIGUOUS SIDES OF SAID BIVALVULAR MEMBERS RESPECTIVELY, ONE OF THE BLOCKS IN EACH PAIR CARRYING A SHEAR-RESISTING PIN, AND THE OTHER BLOCK IN SAID PAIR HAVING A MATCHING BORE IN WHICH SAID PIN IS RECEIVED. 